WHAT SCIENCE AND SUPER-ACHIEVERS TEACH US ABOUT HUMAN POTENTIAL

The book

The author

David Shenk is the national bestselling author of five previous books, including The Forgetting ("remarkable" - Los Angeles Times), Data Smog ("indispensable" - New York Times), and The Immortal Game ("superb" - Wall Street Journal). He is a correspondent for TheAtlantic.com, and has contributed to National Geographic, Slate, The New York Times, Gourmet, Harper's, The New Yorker, NPR, and PBS.

January 12, 2009

It makes absolutely no sense that I should take on Steven Pinker on the subject of genetics. A distinguished Harvard professor of psychology, best-selling writer and popular lecturer, Pinker is one of the best-known and presumably most-respected scientists in the world.

I have a B.A. in English from some college in Rhode Island.

Pinker has been a director of Cognitive Neuroscience at MIT and a few years ago was named by Time magazine as one of the 100 most influential people in the world. He has twice been a finalist for the Pulitzer Prize.

I was recently invited on an internet radio show to talk about my obsession with Jerry Garcia.

On stage in a debate with Pinker, I would last about 90 seconds. And even that would be a privilege, since my chance of ever getting to debate him directly are about as good as becoming an Olympic archer. (I don't arch).

And yet, I am simply compelled by what I know to write that there is something fundamentally misleading -- or at least missing -- about Pinker's characterization of how genes affect us.

To be sure, he gets most of it right. But in his 8000-word article published in yesterday's New York Times Magazine, he never once acknowledges gene-environment interaction or epigenetics, and gives no real attention to, or explanation of, genetic expression. He refers once to the "probabilistic" nature of genes, but does not begin to explain how a gene can lead to probability as opposed to a certainty.

Maybe I'm reading his piece unfairly -- please tell me if you think so -- but to my eye he puts by far the strongest emphasis on the unrelenting power of genes in the formation of human traits. Yes, the piece is filled with small caveats. But this paragraph leaves, I think, an overwhelming impression:

"The most prominent finding of behavioral genetics has been summarized by the psychologist Eric Turkheimer: “The nature-nurture debate is over. . . . All human behavioral traits are heritable.” By this he meant that a substantial fraction of the variation among individuals within a culture can be linked to variation in their genes. Whether you measure intelligence or personality, religiosity or political orientation, television watchingor cigarette smoking, the outcome is the same. Identical twins (who share all their genes) are more similar than fraternal twins (who share half their genes that vary among people). Biological siblings (who share half those genes too) are more similar than adopted siblings (who share no more genes than do strangers). And identical twins separated at birth and raised in different adoptive homes (who share their genes but not their environments) are uncannily similar."

Turkheimer did say that. The quote is correct. But Turkheimer has produced a study showing close to zero heritability with respect to some of these same traits. Heritability studies are frought with complexity and ambiguity. Pinker must know this and is choosing for some reason not to acknowledge it. The last line in the paragraph above is particularly problematic. I'm trying to choose my words carefully, but I would go so far as to say that Pinker's sentence is more false than true. Yes, some identical twins separated at birth have some uncanny similarities -- but many of them also turn out to have not actually been separated at birth. Others are not similar at all.

I have none of Pinker's credentials, but I've read enough to say confidently that the word "heritable" should never be used so casually in a New York Times article, for the very simple reason that it does not mean what non-scientists think it means. Pinker's quick follow-up definition doesn't help. He allows the quote and the entire paragraph to leave the impression that scientists have proven beyond a shadow of a doubt that people
inherit portions of their intelligence,
personality, and religiosity.

If you read his caveats elsewhere very carefully, he backtracks by saying that a lot of
different elements go into it. But in the public explanation of science, it's
all a matter of emphasis and Pinker's emphasis is clear. He's still spending
most of his energy trying to fight against the blank-slaters who once-upon-a-time naively argued
against any genetic influence whatever. We're past that argument now -- or
should be. We know that genes influence everything but directly determine very
little. We know that most traits, particularly complex character traits and
abilities, are the consequence of development. From the moment of conception,
genes interact with the environment. People are not born with fixed IQs.
Talents are not determined by a genetic lottery. Each one of us is conceived
with immense potential.

The nature-nurture debate has not been settled in favor of nurture, as Pinker implies. It's been rendered obsolete.